The NFkB family of transcription factors is essential for initiating the macrophage response to recognition of LPS, a gram negative bacterial cell wall component. This response involves the upregulation of factors required for inflammation, chemoattraction of other immune cells, and production of host defense molecules, which, if not kept in check, can lead to septic shock. This proposal aims to understand whether NFkB family members act redundantly or have specific functions in the macrophage LPS response pathway, by analyzing over time how a set of genes important in this response are regulated by NFkB. Quantitative Real Time PCR will be used to analyze the kinetics of transcription of these genes, and NFkB subunit binding will be asessed using chromatin immunoprecipiation. To address NFkB subunit reduncancy, transcription and NFkB subunit binding will be analyzed in RAW cells knocked down for NFkB expression with RNA interference, as well as in primary bone marrow macrophages from a variety of NFkB mouse knockouts. These data will be used to generate a computational model of NFkB activity that will determine how NFkB transcription factors coordinate their efforts to regulate a specific transcriptional response to LPS in macrophages. [unreadable] [unreadable] [unreadable]